The only other load some ribs have is from the control surfaces, which do come in at the end... Maybe tradition has it you hang the weight on the end and that buys you both the rib strength and the control surface loads. Still though, it seems conservative to put all of the load onto the rib when 1/2 or more of it is on the D-tube...
--- On Mon, 3/5/12, Philip Lardner <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:
From: Philip Lardner <This email address is being protected from spambots. You need JavaScript enabled to view it.>
Subject: RE: [Carbondragonbuildersandpilots] rib testing
To: This email address is being protected from spambots. You need JavaScript enabled to view it.
Date: Monday, March 5, 2012, 7:14 PM
Hmmm indeed... very interesting to see that pressure distribution article. As you point out, the majority of the pressure on the rib appears to be located in the nose section or near the centre diagonal of the rear of the rib, and a more even load distribution along the rib cap might be a more apropriate test.
I still have that last root rib to re-glue to a batten for mounting on the test stand, so I will experement with a more distributed load test and will see how it performs. I imagine it will have a dramatic effect on the magnitude of twisting at high load (there should be much less twist with much o the weight taken off the extreme rear of the rib) and I would happily wager it will take a much greater load before the rib fails. This could be fun!
IF the results are good then it might be possible to reduce the depth of the ribs even more = less weight.
Hmmm...
Phil.
